I just removed the Old Classic FAST Bank to Bank on the Bustang....
Going with a 4L80E and the Holley Dominator System.
You need to order the 558104 Harness for it and terminate the ends to your sensors. (all standard GM stuff)
You can run the Smart Coils so you are coil on plug.
The 558312 Harness is for the Smart coils. (Being sold in the next week)
You can control all transmission,Boost,Engine,Their own Meth injection which is very nice and progressive
Datalog it all on one. It's better at holding AFR's than the FAST and is easier to use.
If you add up all the stuff you'd need to do what the Holley system can do you'd be way over the cost of this one system.
I doubt they are going to make a Buick harness.... It's a engine/car that just isn't popular anymore.... and is shrinking every year.
Making the 558104 harness isn't a big deal. Should only have 3-4hrs in laying the wires out and putting connetors on them.
Hope that helps,
Scott~